mesonexchange

Meson exchange is a framework in hadron physics in which interactions between color-neutral hadrons are described as being transmitted by mesons such as pions, kaons, rho mesons, and omega mesons. The idea, proposed by Yukawa in 1935, was that the finite range of the nuclear force arises from the exchange of a light meson whose mass sets the range.

In the one-boson-exchange picture, the nucleon-nucleon potential is built from single-meson exchanges with couplings constrained by symmetry and fitted to data. The resulting potential has a long-range one-pion contribution, an intermediate-range part from heavier mesons and two-pion exchanges, and a short-range repulsion often attributed to heavier vector mesons.

Applications include phenomenological nucleon-nucleon potentials (such as Paris, Bonn, Nijmegen) and hyperon-nucleon interactions. In contemporary theory these models are viewed as effective descriptions; chiral effective field theory provides a systematic framework with pions and nucleons, treating heavier resonances either implicitly or via resonance saturation.

Limitations include model dependence and a lack of direct link to the underlying quark-gluon dynamics of QCD. Meson-exchange remains a practical tool for low-energy hadronic physics but must be complemented by more fundamental approaches at higher energies or inelastic channels.

Related topics include meson-exchange currents in nuclear electromagnetic and weak processes, vector meson dominance, and two-pion exchange mechanisms.